Chronic Pelvic Pain (CPP) is one of the most common medical problems affecting women today. Chronic pelvic pain occurs in the pelvic and/or abdominal region (e.g., beneath the umbilicus) and can last for up to six months or longer. Although men may also suffer from CPP, the majority of CPP patients are women. The prevalence of CPP among adult female populations in the United States and in the United Kingdom is estimated to be between fifteen and thirty-eight percent.
Diagnosis and treatment of CPP accounts for ten percent of all out-patient gynecologic visits, twenty percent of laparoscopies, and twelve to sixteen percent of hysterectomies at a cost of $2.8 billion annually in the United States. In spite of these invasive efforts, however, 1.5 million CPP patients in the United States alone remain refractory to treatment.
The personal cost to those suffering from CPP is even greater, affecting all aspects of their lives. About twenty-five percent of patients who suffer from CPP are bedridden for much of the day. Fifty-eight percent of CPP patients are forced to cut down on their usual activity one or more days per month. Almost ninety percent of CPP patients suffer pain during sexual intercourse. Many patients who suffer from CPP also experience sleep disturbance, constipation, diminished appetite, retarded body movements and reactions, emotional distress, and depression.
Chronic pelvic pain may be caused by a number of different disorders or injuries. For example, gynecologic conditions account for approximately ninety percent of all cases of CPP. Gastrointestinal diseases, such as irritable bowel syndrome, are the next most common diagnostic category. CPP may also be caused by systemic disorders and problems relating to a specific organ system, such as the urinary tract.
Endometriosis is the most common etiology of CPP in populations with a low prevalence of sexually transmitted diseases. By comparison, chronic pelvic inflammatory disease (PID) is one of the most common gynecologic conditions causing CPP in populations that do have a high prevalence of sexually transmitted diseases.
Although any one disorder may be the cause of CPP, CPP may also be caused by a combination of disorders. In some patients, the etiology of CPP cannot be determined. The absence of a clear diagnosis of CPP can frustrate both patients and clinicians.
Patients with CPP often have coexisting disorders or problems such as somatization disorders, drug and narcotic dependency, physical and sexual abuse experiences, mental health problems, and depression. For example, studies have shown that up to seventy percent of women with CPP have a coexisting somatization disorder. Patients with multiple physical complaints not fully explained by a known general medical condition may be given the diagnosis of somatization disorder. The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (4th edition) criteria for this diagnosis requires the presence of at least four different sites of pain, two gastrointestinal symptoms other than pain, one neurological symptom, and one sexual or reproductive problem other than pain.
As mentioned, CPP is often accompanied by drug dependency. For example, many women with CPP consume narcotics on a regular basis. In addition, some women with CPP have underlying neuropsychiatric problems (e.g., an enhanced sensitivity to pain stimuli) that place them at risk for addiction. Hence, CPP may be remedied in part by discontinuing the consumption of narcotic analgesics and replacing them with pain medications that have a low abuse potential (e.g., low dosages of tramadol).
Studies have also shown that up to twenty-five percent of women with CPP have a history of physical and sexual abuse. These traumatic experiences can alter neuropsychological processing of pain signals and can permanently alter pituitary-adrenal and autonomic responses to stress. Such alterations of the neuropsychological processing of pain signals may instigate and/or promote CPP.
One common type of CPP is interstitial cystitis. Interstitial cystitis is characterized by urinary urgency, bladder discomfort, and a sense of inadequate emptying of the bladder. Dyspareunia is often present. Some women with interstitial cystitis experience pain in the lower abdomen. Pain associated with interstitial cystitis may be due to abnormal bladder epithelial permeability. Optimal treatment of interstitial cystitis is unclear.
Patients with CPP currently have very few treatment alternatives. CPP is often poorly controlled by medication. Surgery is often ineffective, as the pain may persist even after surgery. CPP may also be controlled through the use of a transcutaneous electrical nerve stimulation (TENS) system which masks local pain sensations with a fine tingling sensation. However, TENS devices can produce significant discomfort and can only be used intermittently.